platform / x86 / PM: Fix unused function warnings for CONFIG_PM_SLEEP

According to compiler warnings, quite some suspend/resume functions
in platform x86 drivers are not used for CONFIG_PM_SLEEP unset, so
add #ifdefs to prevent them from being built in that case.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/platform/x86/hp_accel.c b/drivers/platform/x86/hp_accel.c
index f4d9115..6b9af98 100644
--- a/drivers/platform/x86/hp_accel.c
+++ b/drivers/platform/x86/hp_accel.c
@@ -352,7 +352,7 @@
 }
 
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int lis3lv02d_suspend(struct device *dev)
 {
 	/* make sure the device is off when we suspend */